<template>
   <div>
       <h1>当前求和为:{{sum}}</h1>
       <select v-model.number="n">
            <option value="1">1</option>
            <option value="2">2</option>
            <option value="3">3</option>
       </select>
       <button @click="increment">+</button>
       <button @click="derement">-</button>
       <button @click="incrementOdd">当前求和为奇数在加</button>
       <button @click="incrementWait">等一等在加</button>
   </div>
</template>

<script>
    export default {
       name:'Count',
       data(){
            return{
                n:1, //用户选择的数值
                sum:0//当前的和
            }
        },
        methods:{
            increment(){
                this.sum+=this.n
            },
            derement(){
                this.sum-=this.n
            },
            incrementOdd(){
                if(this.sum%2){
                    this.sum+=this.n
                }
            },
            incrementWait(){
                setTimeout(()=>{
                    this.sum+=this.n
                },500)
            }
        }
    }
</script>
<style scoped>
  button{
      margin-left: 5px;
  }
</style>
